warp.noise
==========

.. function:: warp._src.lang.noise(state: uint32, x: float32) -> float

   .. hlist::
      :columns: 8

      * Kernel
      * Python
      * Differentiable

   Sample 1D non-periodic Perlin noise.
   
   Samples a smooth, deterministic field on an integer lattice with one cell per input
   unit. ``state`` selects the field and is not advanced. Scale the coordinate to
   change feature size and the result to change amplitude.
   
   The field is differentiable with respect to the coordinate. For a given Warp version
   and device backend, results are deterministic for fixed inputs. Exact values may differ
   between CPU and CUDA or change between Warp versions. Use :func:`pnoise` for periodic noise.
   
   When a coordinate component's magnitude reaches ``2^23`` (about 8.4e6), ``float32``
   spacing is at least one input unit, so the field may lose variation. Coordinate
   components must currently remain within the signed 32-bit lattice-index range.
   
   :param state: RNG state that selects the noise field (see :func:`rand_init`); never advanced.
   :param x: Coordinate to sample. One noise feature spans one unit.
   
   :returns: The noise value at ``x``. Values across the field are centered on zero.
   
   .. rubric:: Example
   
   .. testcode::
   
       @wp.kernel
       def sample_noise(seed: int, coords: wp.array[float], values: wp.array[float]):
           tid = wp.tid()
           state = wp.rand_init(seed)
           values[tid] = wp.noise(state, coords[tid])
   
       coords = wp.array([0.5, 2.25, 4.75], dtype=float)
       values = wp.zeros(len(coords), dtype=float)
   
       wp.launch(sample_noise, dim=len(coords), inputs=[42, coords], outputs=[values])
   

.. function:: warp._src.lang.noise(state: uint32, xy: vec2f) -> float
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel
      * Python
      * Differentiable

   Sample 2D non-periodic Perlin noise.
   
   See :func:`noise` for shared behavior, restrictions, and a usage example.
   
   :param state: RNG state that selects the noise field (see :func:`rand_init`); never advanced.
   :param xy: Coordinate to sample. One noise feature spans one unit.
   
   :returns: The noise value at ``xy``.
   

.. function:: warp._src.lang.noise(state: uint32, xyz: vec3f) -> float
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel
      * Python
      * Differentiable

   Sample 3D non-periodic Perlin noise.
   
   See :func:`noise` for shared behavior, restrictions, and a usage example.
   
   :param state: RNG state that selects the noise field (see :func:`rand_init`); never advanced.
   :param xyz: Coordinate to sample. One noise feature spans one unit.
   
   :returns: The noise value at ``xyz``.
   

.. function:: warp._src.lang.noise(state: uint32, xyzt: vec4f) -> float
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel
      * Python
      * Differentiable

   Sample 4D non-periodic Perlin noise.
   
   The fourth coordinate is commonly used as time to animate a 3D field. See
   :func:`noise` for shared behavior, restrictions, and a usage example.
   
   :param state: RNG state that selects the noise field (see :func:`rand_init`); never advanced.
   :param xyzt: Coordinate to sample. One noise feature spans one unit.
   
   :returns: The noise value at ``xyzt``.